What was will be
Olympia is set to be the planet of refuge. Far, far away from Earth, it was the only available planet left in the galaxy, unclaimed or uncolonized by any state or prethoryn. It was a size 25 planet, although a glacier world, but humans are adaptable - it'd have to do. Earth sets about relocating as many of its people as it could to Olympia, but relocation was slowed by two factors: The planet itself contained many hostile organisms, glaciers and mountains which needed accommodation before anything from Earth could live there, and the nature of the forced evacuation caused the Liberty faction to withdraw its support and so greatly reduce the political influence available to evacuation planners. Every human moved to Olympia was replaced by a placeholder robot nation pop; while there was no way to build the required amount of robots needed to replace the evacuated humans, it was a good excuse to covertly stop humans on Earth from producing children. The young would be spared the sight of Prethoryn infestation if we could allow it.
A place... Decidedly colder than Earth. Work at once involved the construction of new habitats and ecology parks, with Earth selling its research to the other states for energy and minerals, with such funds going to the development of new industry and plans for a science nexus.
Many raids had been launched against the Prethoryn by the Propitious Pact and the Bright Entente, whose largest members included the Adnori State and Belmacosa Republic respectively. This continual series of raids prevented the Prethoryn from making further advances for many years, as they spent much time hunting down invading squadrons spread over a vast galactic plane. On this year the Belmacosans would engage in the largest fleet battle against the Prethoryn anyone had ever made. They suffered tremendous casualty, but tied down many fleets:
While the Adnori attacked on the Northern front. While we lacked the funds and time needed to replace the 5th fleet, our psionic avatar piloted by Admiral Petrenko, the Chosen One, soaked up a hell of a lot of Prethoryn time and scored many kills against swarmlings and stations. Admiral Petrenko would remain in a solar system for as long as possible, drawing as many Prethoryn fleets as deep into the core of a star's gravity well before emergency jumping out of the system, thus leaving many more weeks between the travel time of the swarms and a habitated allied world. Thus the two federations actually held the ocean at bay.
We contacted the Electronic Succsphere. We figured it was the end of the world so we might as well.
It lay inside of the Prethoryn Scourge's infested space, but it seemed the Succsphere was the only thing in the recorded galaxy the Scourge did not attack.
The sphere was very polite, and we decided to help it. We sent our most valuable scientist forth to aid their efforts, and despite being deep within prethoryn space, no fleets approached near our scientist when they were by the sphere.
A Ganvius Regime fleet got locked into combat with the Prethoryn. On this year it would be the single largest concentration of Prethoryn warships ever recorded, with an estimated fleet power of over 1,484,000. The largest allied fleet ever recorded was a Belmacosan one at around 70,000.
2432: Humanity makes their first research innovation in decades, as humanity once more turns to research instead of production.
The Sol system had dealt with category I Prethoryn invasions and even category II Prethoryn invasions, but in the year of 2433 the Sol system was hit with a Category V Prethoryn Invasion. In two months the Prethoryn annihilated all of our Fortresses, over 500,000 overwhelming all of our guns and fighter craft. It is unknown why the Prethoryn attacked Sol in such great numbers, but this invasion was the largest invasion ever recorded against any planet system. It seemed as if the swarm had learned to prioritize Earth as the primary obstacle to their continued murder of the universe.
The Prethoryn ignored their heavy casualties. They were without number
We left 4 pops behind, unable to evacuate any more. Even our attempt to evacuate the army failed, only the psionic avatar escaped successfully.
The evacuation was a major success however, despite those we left behind. Olympia had been settled and left with a nascent industry with which to continue their megastructure project. There was hope now that we could develop ships powerful enough to contain the Prethoryn expansion.
Even though we have left Earth so hard that Earth doesn't even exist anymore, we spent decades researching until we finally gained the ability to create Gaia Worlds. If ever we reclaim Sol, we can rebuild Earth better.
The last 3 decades have been us non-stop saying goodbye to the pops we once knew, and this one hurt. With the fall of Fortress Sol the Prethoryn swiftly moved on to invade Iblyria, putting an end to our Mandasuran friends. Goodbye my sweet leafs, you didn't deserve this.
Every single Empire is sharing information, research and border access to fight the Prethoryn, with every Empire being a member of the Propitious Pact or the Bright Entente. Admiral Petrenko is still continuing her Avatar raids upon Prethoryn space (and has even destroyed two more worlds!) but with the fall of Fortress Sol, the Prethoryn have also begun expanding their frontiers once more. The fight is not yet lost.